High-resolution phase-contrast X-ray imaging for biological soft tissue
High-resolution phase-contrast X-ray imaging for biological soft tissue lead image
Medical X-ray imaging is perhaps best known for the diagnosis of broken bones. For broader applications, phase-contrast X-ray imaging can produce high-contrast three-dimensional images for the pathological diagnosis of surgically removed tissue and the study of micro-regional anatomy. These uses require high-resolution images for the microscopic examination of multiple tissue sections.
Conventional phase-contrast methods require the object and image detector to be separated to an optimal distance. In principle, increasing that distance lowers the spatial resolution, which poses a challenge for capturing minute details such as the cell nuclei shape needed for pathological diagnosis. Sunaguchi et al. developed the Superimposed Wavefront Imaging of Diffraction-enhanced X-rays (SWIDeX) method for a shorter detector-to-sample distance.
“In the spatial X-ray interference method and analyzer-based methods, the X-ray image must be acquired at a certain distance from the sample after the X-rays propagate through the sample, which is necessary for the interference of X-ray wavefronts or the separation of X-ray diffracted images,” said author Naoki Sunaguchi.
SWIDeX minimizes the detector-to-sample distance by detaching the scintillator, which converts the X-ray image into a visible image, from the detector and placing it in close contact with the Laue-case angle analyzer.
Though this increases the spatial resolution significantly the analyzer must be 20 micrometers thin to achieve the desired one-micrometer goal, requiring high-precision polishing and installation methods that are still in development.
“We hope to visualize the distribution and shape of cell nuclei in vivo in three dimensions with higher resolution in the future,” Sunaguchi said.
Source: “Superimposed wavefront imaging of diffraction-enhanced X-rays: A method to achieve higher resolution in crystal analyzer-based X-ray phase-contrast imaging,” by Naoki Sunaguchi, Tetsuya Yuasa, Daisuke Shimao, Shu Ichihara, Rajiv Gupta, and Masami Ando, Applied Physics Letters (2023). The article can be accessed at https://doi.org/10.1063/5.0139199 .
